Kabul, Afghanistan (CNN) -- The head of Afghanistan's Independent Election Commission vowed Saturday that he would not support a coalition government in Afghanistan.

IEC President Azizullah Lodin told CNN if the parties of President Hamid Karzai and his rival, Abdullah Abdullah, decide on a coalition government instead of having a presidential election run-off vote on November 7, he will warn "that is against the law, against the constitution."

Karzai's representatives met Saturday in 11th-hour talks with Abdullah's representatives. Abdullah's spokesman would not elaborate on the meeting, but the candidate was expected to make an announcement Sunday morning.

Lodin said he was not informed of the planned meeting and had no details from the talks.

Karzai agreed to the November runoff election after intense diplomatic arm twisting by the United States. He claimed victory in the first round of voting in August, but an investigation revealed widespread fraud.

The United Nations has warned the election commission not to rehire any election workers who broke rules or committed illegal actions.

Lodi said it was not the United Nations' place to make these demands. He said the commission already had decided not to rehire some of the workers. Instead of 165,000 election workers, there will only be between 60,000 and 70,000 this time, he said.

He said the commission plans to keep all polling stations open, and would do its best to prevent fraud.

With "23,000 sites, with 6,322 centers, who can control this area? The only thing we can do, we will leave that to the conscience of these people that are working there," he said.

Abdullah has called for the resignations of top election officials and politicians to avert electoral fraud a second time around. He argued that the commissioners cannot be impartial because of their bias toward Karzai.

Lodin has denied any wrongdoing and said that unless Abdullah has proof of such bias he is in no position to ask any Afghan official to step down.

A Western source close to the Afghan leadership told CNN's Christiane Amanpour on Friday that talks between Karzai and Abdullah, his former foreign minister, had broken down. Saturday's talks offered a glimmer of hope.

Former U.S. Ambassador to Afghanistan Zalmay Khalilzad predicted earlier this week that the country would soon be governed under a power-sharing deal.

"First, he doesn't have much money left," he said. "Second, I think that he thinks that, given the situation, he's likely to lose, and maybe he'll get less votes than he did in the first round, so that would be embarrassing."

Some have questioned the legitimacy of any government that might result from a runoff with only one candidate standing. But U.S. Secretary of State Hillary Clinton said Saturday the situation would not be unprecedented.

"Other countries have faced this, where one candidate decides not to go forward," she said. "We see that happen in our own country where, for whatever combination of reasons, one of the candidates decides not to go forward. I don't think it has anything to do with the legitimacy of the election. It's a personal choice which may or may not be made."

President Obama is considering whether to send more troops to Afghanistan to fight the Taliban insurgency, as requested by the commander of troops there, Gen. Stanley McChrystal.

Khalilzad said the outcome of the Afghan election negotiations is crucial to whatever decision the U.S. president makes.

"This will be one last chance to push for success in Afghanistan," he said. "And that cannot happen without the Afghan leaders doing their part."

Hundreds of thousands of fraudulent ballots were tossed after the first round of voting in August, which left Karzai with less than the 50 percent plus one votes needed for victory.